The present paper concerns developing an automated system for non-destructive evaluation of riveted aluminium joints. The system features an innovative eddy-current probe providing high sensitivity at low inspection frequencies and a computational tool aimed both at computer-aided electromagnetic design of the probe and quantitative reconstruction of detected defects (inverse problem). The approach adopted for defect reconstruction exploits numerical solution of the forward problem. It is based on the edge element integral formulation of the eddy current problem and offers fast and accurate numerical modelling. The inspection cases in focus represent multi-layered aluminium structures with tiny cracks propagating from fastener holes in the subsurface layers. Accurate and fast numerical modelling proved to be a valuable tool for automated quantitative crack reconstruction and optimisation of an eddy current probe. The improved probe design yielded easy cracks discrimination and reduced sensitivity to vertical tilting. Main achievements in numerical modelling constitute: (1) gain of confidence in numerical simulation tools by comparison with experimental data (artificial cracks) which confirms the feasibility of the quantitative crack reconstruction; (2) improved efficiency of the simulation tool by tuning fast, reliable and accurate numerical models. Further advances of the presented computational tool concern natural thin cracks with finite resistivity as well as 3D volumetric defects. The future development will address: (1) constructing a two-coil probe with accurate sensor positioning; (2) tests on natural cracks; (3) in field applications.
A computational technique for automated recognition of subsurface cracks in aeronautical riveted structures
Ein Berechnungsverfahren zur automatischen Erkennung von Rissen unter der Oberfläche in genieteten Luftfahrtstrukturen
2004
8 Seiten, 10 Bilder, 2 Tabellen, 7 Quellen
(Nicht paginiert)
Conference paper
Storage medium
English
Energy absorption of riveted structures
Automotive engineering | 1999
|Energy absorption of riveted structures
British Library Conference Proceedings | 1999
|